Intramedullary nails

ABSTRACT

The present invention is generally directed to intramedullary nails that can include a keel configured for rotational stabilization and/or a multi-sectioned rod configured to apply compression to a fracture.

FIELD OF THE INVENTION

The present invention relates to intramedullary nails and methods ofinstallation thereof.

BACKGROUND OF THE INVENTION

Traumatic injuries to the skeletal system can be treated in a variety ofways. In general, treatments may include reducing or restoring anydisplaced bone fragments into proper alignment, and immobilizing thebones so that they can heal. Some fractures can be treatednon-invasively, such as through the use of a cast or splint; otherfractures may require a surgically-applied stabilization device.

Surgical devices used to stabilize broken bones can include, forexample, plates, pins, screws, nails, and/or some combination thereof.When the bone that is fractured or broken is a long bone, such as thefemur, tibia, fibula, humerus, radius, and ulna, an intramedullary nailmay be used for treatment. An intramedullary nail can include a rod thatis placed in the medullary canal of a broken bone and secured to theproximal and distal ends of the bone with locking screws. In use, anintramedullary nail can help to immobilize a broken bone while alsoreducing the weight or load being placed on the bone.

SUMMARY OF THE INVENTION

One drawback of current intramedullary nails is that the insertion andlocking of the nail may occur in two separate steps, as the rod is firstinserted into the medullary canal and subsequently fixed in place by thelocking screws. Since the rod is not fixed in place upon insertion, itmay rotate undesirably within the medullary canal. Additionally, amulti-step process can require a significant amount of time. Anotherdrawback of current intramedullary nails is that reduction and/orcompression of the bone fragments may take place separately from rodinstallation. Some compression techniques may also involve the use ofadditional screws, which can result in added trauma to the surroundingarea. Furthermore, a multi-step process can require a significant amountof time, and multiple components can increase the complexity of theprocedure. Accordingly, there exists a need for new and improvedintramedullary nails.

Some embodiments herein are directed to an intramedullary nail that caninclude a rod comprising a proximal portion and a distal portion, and atleast one elongate keel disposed longitudinally on an outer surface ofthe rod.

Other embodiments are directed to a method of installing anintramedullary nail that can include providing an intramedullary nailcomprising a rod having a proximal portion, a distal portion, and atleast one elongate keel disposed longitudinally on an outer surface ofthe rod; cutting at least one groove within a medullary canal, whereinthe groove is configured to receive the elongate keel; and inserting theintramedullary nail into the medullary canal such that the elongate keelis received in the groove.

Some embodiments herein are directed to an intramedullary nail that caninclude a rod comprising a proximal portion, a distal portion, and anouter surface; and a deployable keel oriented longitudinally along therod; wherein the deployable keel is configured to transition from aretracted position to a deployed position.

Other embodiments are directed to a method of installing anintramedullary nail that can include providing an intramedullary nailcomprising a rod having a proximal portion, and a distal portion, atleast one deployable keel oriented longitudinally along the rod and in aretracted position; cutting at least one groove within a medullarycanal, wherein the groove is configured to receive at least a portion ofthe deployable keel; inserting the intramedullary nail into themedullary canal; and deploying the deployable keel to transition fromthe retracted position to a deployed position, such that the deployablekeel is received in the groove.

Some embodiments herein are directed to an intramedullary nail that caninclude a rod comprising a proximal portion and a distal portion andconfigured to transition from an expanded configuration to a compressedconfiguration; a compression mechanism configured to move the proximaland distal portions axially with respect to one another from theexpanded configuration to the compressed configuration; and an actuatorassembly configured to actuate the compression mechanism and comprisingan actuator located on the proximal portion of the rod.

Other embodiments are directed to a method of installing anintramedullary nail that can include providing an intramedullary nailcomprising a rod comprising a proximal portion and a distal portion andconfigured to transition from an expanded configuration to a compressedconfiguration, a compression mechanism configured to move the proximaland distal portions axially with respect to one another, and an actuatorassembly configured to actuate the compression mechanism and comprisingan actuator located on the proximal portion of the rod; inserting theintramedullary nail in the expanded configuration into a medullary canalof a fractured bone, the fractured bone comprising a first bone fragmentand a second bone fragment separated by a first distance; securing thedistal portion to the first bone fragment; and actuating the compressionmechanism to transition the rod from the expanded configuration to thecompressed configuration, such that the distal portion and the firstbone fragment are moved axially to a second position wherein the firstand second bone fragments are separated by a second distance that isless than the first distance.

Further areas of applicability of the present invention will becomeapparent from the detailed description provided hereinafter. It shouldbe understood that the detailed description and specific examples, whileindicating the preferred or exemplary embodiments of the invention, areintended for purposes of illustration only and are not intended to limitthe scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is a side view of an embodiment of an intramedullary naildisclosed herein;

FIGS. 2A-B illustrate variations on front views of an intramedullarynail disclosed herein;

FIG. 3 is a detail view of an elongate keel disclosed herein;

FIG. 4 is a side view, in partial cross-section, of an embodiment of anintramedullary nail disclosed herein;

FIG. 5A is a detail view of one embodiment of a deployable keel in aretracted position;

FIG. 5B is a detail view of one embodiment of a deployable keel in adeployed position;

FIG. 6 is a schematic view of an embodiment of an intramedullary nailincluding a compression mechanism disclosed herein; and

FIG. 7 is a schematic side view of one embodiment of a proximal end ofan intramedullary nail including a compression mechanism disclosedherein.

FIG. 8 is a cross-sectional view of one embodiment of an intramedullarynail including a compression mechanism including ramps.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Embodiments herein are generally directed to intramedullary nails thatcan include a fixation feature and/or a compression element. Inembodiments that include a fixation feature, a separate locking screwmay not be needed. Accordingly, these intramedullary nails may beconfigured for insertion and locking in a single step. Furthermore, evenif used in combination with a separate locking screw, theseintramedullary nails can provide more stable placement as compared toother intramedullary nails that do not include a fixation feature.Compression of bone fragments, for example, through the application ofcompression plates, has been used to promote healing by pushing orpulling the fragments together, thereby reducing the gap that must befilled by new bone growth. Embodiments herein that include a compressionelement may thus advantageously combine the benefits of anintramedullary nail with the benefits of axial compression. Furthermore,although these features may be discussed separately herein, it should beappreciated that intramedullary nails that include any combination ofthese features are within the scope of the present disclosure.

Turning to FIG. 1, some embodiments herein are directed to anintramedullary nail 2 that can include a rod 4 having a proximal portion6 and a distal portion 8. The rod 4 can be sized and configured to fitwithin a medullary canal of a long bone, such as a femur, tibia, fibula,humerus, radius, and/or ulna. For example, when configured for placementwithin a femur, the rod 4 can have a length, extending from a proximalend to a distal end, in the range of from about 30 cm to about 50 cm,and a diameter in the range of from about 0.5 cm to about 2 cm. Asanother example, when configured for placement within a humerus, the rod4 can have a length, extending from a proximal end to a distal end, inthe range of from about 15 cm to about 35 cm, and a diameter in therange of from about 0.5 cm to about 1.5 cm. It can be manufacturedaccording to techniques known in the art and can be machined from anysuitable materials, including metals such as titanium, titanium alloys,and stainless steel. In some embodiments, the rod can be straight; inother embodiments, the rod can be curved to conform to the shape of themedullary canal and/or other anatomical feature. The rod 4 can have agenerally round cross section with either a constant or variable outerdiameter. The rod 4 can include a longitudinal axis 16 that extends froma proximal end to a distal end. In some embodiments, the rod can besolid. In other embodiments, the rod can be hollow. For example, the rodcan include a lumen extending longitudinally therethrough. The lumen canhave a constant or variable diameter. The distal end of the rod 4 caninclude a distal tip 10. In some embodiments, the distal tip 10 can betapered to facilitate insertion of the rod into the medullary canal.

The intramedullary nail 2 can further include at least one fixationfeature, such as an elongate keel 12. The elongate keel 12 can act as ananti-rotation mechanism, e.g., it can advantageously inhibit or reducerotation of the intramedullary nail 2 within the medullary canal. Theelongate keel 12 can be disposed longitudinally on an outer surface 14of the rod 4. For example, the base 23 of elongate keel 12, illustratedin FIG. 3, can extend parallel to the longitudinal axis 16 of the rod 4.In some embodiments, the intramedullary nail 2 can include a pluralityof elongate keels. The elongate keels can be distributed anywhere alongthe outer surface 14 of the rod 4 with respect to its length and/orcircumference. As illustrated in FIG. 1, the proximal portion 6 and thedistal portion 8 can each include a plurality of elongate keels. In someembodiments, the elongate keels can be staggered along the length of therod 4. In other embodiments, the rod 4 can include a first row 18 ofelongate keels situated at the same longitudinal position along the rod4, as illustrated in FIG. 1 with respect to elongate keels 12 a and 12b. It is noted that specifically identified elongate keels 12 a-d asdiscussed herein can include any and all of the same features disclosedin general with respect to elongate keel 12. In some embodiments, therod 4 can include two or more rows of elongate keels distributedthereon. For example, the rod 4 can include a first row of keels on theproximal portion 6 and a second row 20 of keels on the distal portion 8.The elongate keels can be disposed anywhere around the circumference ofthe rod. As illustrated in FIG. 2A, the first and second rows of keels18, 20 can be aligned around the circumference the rod 4. In otherembodiments, such as that illustrated in FIG. 2B, the first and secondrows of keels 18, 20 can be staggered around the circumference of therod 4. As further illustrated in FIGS. 2A-B, the elongate keels cangenerally extend orthogonally from the outer surface 14 of the rod 4. Inother embodiments, one or more elongate keels may extend from the outersurface 14 of the rod 4 at another angle between 0° and 180°.

Turning to FIG. 3, the details of one example of an elongate keel 12 areillustrated. The elongate keel 12 can include a base 23 and an edge 24.The elongate keel 12 can be attached to the outer surface 14 of the rod4 at the base 23. For example, the base 23 can be welded to the rod 4.In another example, the elongate keel 12 and the rod 4 can be machinedin a single piece. In some embodiments, the edge 24 can be blunt, asillustrated in FIG. 3. In other embodiments, the edge 24 can besharpened (e.g., can include a blade). In yet other embodiments, theedge 24 can be rounded. The edge 24 can be straight from a distal toproximal end, as illustrated in FIG. 3, or it can be curved. Theelongate keel 12 can have a height as measured from the base 23 to theedge 24 and a length as defined by the base 23. In some embodiments, theelongate keel 12 can have a uniform height (e.g., can have a generallyrectangular profile). In other embodiments, the elongate keel 12 canhave a variable height. For example, the elongate keel 12 can have aheight that increases in the proximal direction (e.g., can have agenerally triangular profile). As another example, the elongate keel 12can have a profile in the shape of a right triangle, an obtuse triangle,or an acute triangle. The length of the elongate keel 12 can vary. Insome embodiments, the length can be in the range of from about 5% toabout 30% of the length of the rod 4. In other embodiments, the lengthof the elongate keel 12 can be equal to at least about 10% of the lengthof the rod 4.

Returning to FIG. 1, in some embodiments, the rod 4 can include one ormore screw holes. As discussed herein, some of the present embodimentscan include an anti-rotation mechanism, such as elongate keel 12.Advantageously, these embodiments may be configured for insertion intothe medullary canal and locking therein in a single step. Consequently,separate locking screws may advantageously not be required. Regardless,in some embodiments, such as that shown in FIG. 1, the rod 4 mayoptionally include one or more screw holes 22 a-f configured to receiveone or more locking screws (not shown). In these embodiments, the screwholes and corresponding locking screws can provide supplementalstability. As illustrated in FIG. 1, the screw holes can be distributedaround the circumference of the rod. The screw holes can also bedistributed along the proximal and/or distal portions of the rod. Insome embodiments, the rod can include a plurality of screw holes 22 d-fin the proximal portion and a plurality of screw holes 22 a-c in thedistal portion.

Each screw hole can define a channel that passes through the rod,optionally intersecting its longitudinal axis 16. The channels canintersect the longitudinal axis at any angle. For example, in someembodiments a rod can include a channel that is perpendicular to thelongitudinal axis 16, such as those defined by screw holes 22 a-c. Inother embodiments, a rod can include a channel that intersects thelongitudinal axis at an approximately 45° angle, such as that defined byscrew hole 22 f. The channels can also be distributed along the rod atvarious angles relative to each other. For example, in some embodiments,a first channel and a second channel can pass through the rod atapproximately 90° relative to each other, such as those defined by screwholes 22 b and 22 c, respectively. In other embodiments, a first channeland a second channel can be aligned (e.g., 0° relative to each other),such as those defined by screw holes 22 a and 22 b. In yet otherembodiments, the first and second channels can be staggered by any anglein the range of 0° to 90°.

The screw holes can be of varying shapes and cross-sections. In someembodiments, they can be circular, as illustrated in FIG. 1 with respectto screw holes 22 a-c and 22 f. In other embodiments, they can be ovular(e.g., slots), as illustrated with respect to screw holes 22 d-e. Insome embodiments, the screw holes can have a constant diameter (e.g.,rectangular cross-section). In other embodiments, the screw holes canhave a tapered diameter (e.g., trapezoidal cross-section). When screwsare inserted eccentrically, these screw holes can advantageously act ascompression slots and can be configured to apply compression to thefracture. These compression slots can be used alone or in conjunctionwith the compression mechanisms described herein. Various locking screwscan be received in the screw holes 22 a-f, including but not limited tocortical screws and cancellous screws, as well as fully- andpartially-threaded versions thereof.

Embodiments herein are also directed to methods of installing theintramedullary nail 2. These methods can include providing theintramedullary nail 2 and cutting at least one groove within a medullarycanal (e.g., on an interior surface of a long bone). The groove can besized and configured to receive the elongate keel 12 at least partiallytherein. For example, the groove can have a depth in the range of fromabout 1 mm to about 3 mm. Any cutter known in the art can be used.Subsequently, the intramedullary nail 2 can be inserted into themedullary canal such that at least a portion of the elongate keel 12(e.g., edge 24) is received in the groove. Advantageously, the groovecan act as a track, with the elongate keel 12 sliding therein. Theelongate keel and groove can thus be used to guide the intramedullarynail 2 into the medullary canal. Additionally, the elongate keel 12 canprevent or minimize rotation of the intramedullary nail 2 within themedullary canal.

Methods herein can also include other steps utilized in the art for theinstallation of intramedullary nails. For example, some embodimentsherein can optionally include preparing the medullary canal prior tocutting the groove therein. The preparation step can include, forexample, reduction of a fractured bone within which the medullary canalis situated and/or defining a passageway through the medullary canal(e.g., through the use of a drill, awl, and/or reamer). Optionally,methods herein can also include inserting a locking screw into a screwhole in the intramedullary nail 2. However, as discussed herein, thisstep may not be required, as the elongate keels 12 can providesufficient rotational stability such that additional locking mechanismsare not needed.

Some embodiments herein are directed to an intramedullary nail that caninclude a rod and a deployable keel. One example is intramedullary nail202, illustrated in FIGS. 4-5B. In some embodiments, the intramedullarynail 202 can include a rod 204 having a lumen 226 extendingtherethrough, e.g., between a proximal end 206 and a distal end 208. Insome embodiments, the rod 204 can also include an opening 230. Theopening 230 can be configured to receive at least a portion of thedeployable keel 212. For example, the opening 230 can be rectangular orslot-shaped. As illustrated in FIG. 4, the rod 204 can include aplurality of openings 230 (e.g., 2, 3, 4, 5, 6, or more). The number ofopenings 230 can be equal to the number of deployable keels 212 presenton the intramedullary nail 202. In some embodiments, a proximal cap 232can also be connected to the proximal end 206 of the rod 204. The rod204 can also include other features described herein with respect to rod4 of intramedullary nail 2.

The intramedullary nail 202 can also include a deployable keel 212. Thedeployable keel 212 can be oriented longitudinally along the rod 204,and can be configured to transition from a retracted position to adeployed position. In some embodiments, the transition is reversible(e.g., the deployable keel 212 can transition between the retracted anddeployed positions). FIGS. 5A-B illustrate examples of deployable keel212 in the retracted and deployed positions, respectively. When in thedeployed position, the deployable keel 212 can extend away from the rod.In some embodiments, the deployable keel 212 can include a tip 228(e.g., the tallest point on the deployable keel 212). When thedeployable keel 212 is in the deployed position, the tip 228 can befarther away from an outer surface 214 of the rod 204 as compared towhen the deployable keel 212 is in the retracted position. Asillustrated in FIGS. 5A-B, the deployable keel 212 can pass through theopening 230 of the rod 204 when transitioning from the retractedposition to the deployed position. In some embodiments, when in theretracted position, at least a portion of the deployable keel 212 can bewithin the lumen 226 of the rod 204, and, when in the deployed position,at least a portion of the deployable keel 212 can be outside of thelumen 226. In some embodiments, at least a portion of the deployablekeel 212 can be compressed within the lumen 226 when in the retractedposition. The deployable keel 212 can also include other featuresdescribed herein with respect to elongate keel 12 of intramedullary nail2.

In some embodiments, the intramedullary nail 202 can further include adeployment mechanism. The deployment mechanism can be configured toactuate the transition of the deployable keel 212 from the retractedposition to the deployed position. The deployment mechanism can employvarious components to deploy the deployable keel 212. For example, thedeployment mechanism can include a shaft that is disposed within thelumen 226, and to which the deployable keel 212 is operatively connected(e.g., through a hinge or other linkage). In some embodiments, the shaftcan be configured for linear motion relative to longitudinal axis 216,such that the deployable keel 212 can slide in a proximal-distaldirection from the retracted to the deployed position. In otherembodiments, the shaft can be configured for rotational motion relativeto the longitudinal axis 216, such that the deployable keel 212 canrotate in a clockwise or counter-clockwise direction from the retractedto the deployed position. In yet other embodiments, the shaft mayinclude another component, such as a sliding ring, that can beconfigured for linear and/or rotational movement. In some embodiments,the deployment mechanism can additionally include one or more springsand/or other tension or compression members that can apply force to theshaft and/or deployable keel 212.

Although the components of the deployment mechanism may be distributedthroughout the intramedullary nail 202, at least a portion of thedeployment mechanism may be disposed at the proximal portion 206 of therod 204. For example, an actuator can be located in or adjacent to theproximal cap 232. In some embodiments, the proximal cap 232 can includeone or more of a button, switch, knob, threaded nut, and lever which isconfigured to actuate the deployment mechanism.

In use, a method of installing the intramedullary nail 202 can includeproviding the intramedullary nail 202, wherein the deployable keel 212is in the retracted position. Optionally, the method can include cuttinga groove within a medullary canal as described herein. The groove can beconfigured to receive at least a portion of the deployable keel 212.Subsequently, the intramedullary nail 202 can be inserted into themedullary canal, and the deployable keel can be deployed from theretracted position to the deployed position. If a groove is present, thegroove can receive the deployable keel when in the deployed position. Inembodiments where the intramedullary nail 202 includes a deploymentmechanism, the deployable keel can be deployed by actuating thedeployment mechanism. For example, the deployable keel can be deployedby pushing a button, sliding a switch, turning a knob, threading a nut,and/or pulling a lever located on or in the proximal cap 232.Advantageously, once the keel is deployed, the intramedullary nail 202may be locked and/or stabilized within the medullary canal. Other stepspracticed in the art with respect to installation of intramedullarynails may also be used, as discussed herein. For example, additionallocking elements such as screws, although not required, may optionallybe utilized to provide supplemental stability.

Other embodiments herein are directed to an intramedullary nail that caninclude a compression element. As illustrated in FIG. 6, intramedullarynail 402 can include a rod 404, a compression mechanism 434, and anactuator 436. The rod 404 can include a proximal portion 406, a distalportion 408, and a longitudinal axis 416. Although the proximal anddistal portions 406, 408 are illustrated in FIG. 6 as being ofapproximately equal length, those skilled in the art may appreciate thatin other embodiments, the proximal and distal portions 406, 408 may beof unequal length. The rod can be configured to transition from anexpanded configuration having a first length to a compressedconfiguration having a second length, wherein the second length is lessthan the first length. For example, the rod can be shorter in thecompressed configuration and longer in the expanded configuration. Theproximal portion 406 and/or the distal portion 408 can be configured tomove axially with respect to one another, resulting in expansion and/orcompression of the intramedullary nail 402. For example, the distalportion 408 can be configured to slide along longitudinal axis 416towards and/or away from the proximal portion 406. Conversely, theproximal portion 406 can be configured to slide along longitudinal axis416 towards and/or away from the distal portion 408. The proximal and/ordistal portions 406, 408 can include a lumen extending longitudinallytherethrough. In some embodiments, at least a portion of the proximalportion 406 can be configured to be received within the lumen of distalportion 408, or vice versa. The rod 404 can also include other featuresdescribed herein with respect to the rods of intramedullary nail 2and/or intramedullary nail 202, such as elongate and/or deployablekeels.

The compression mechanism 434 can be configured to move the proximal anddistal portions 406, 408 axially with respect to one another. Variousmechanics that effect linear expansion and/or compression can be used aspart of the compression mechanism 434. In some embodiments, thecompression mechanism 434 can include a compression member, whereinrotation of the compression member results in axial translation of theproximal and/or distal portions 406, 408. The compression member can bedisposed between, around, and/or within the proximal and/or distalportions 406, 408. For example, in one embodiment, the compressionmechanism 434 can include a compression member, such as aninternally-threaded sleeve, rotatably attached around the proximalportion 406 of the rod 404 and configured to mate with externalthreading on the distal portion 408 of the rod 404. In use, when thesleeve is rotated in one direction, it can threadably engage the distalportion 408 and cause the distal portion to slide axially, e.g., in aproximal direction towards proximal portion 406. In some embodiments,the distal portion 408 can be received within a lumen of the proximalportion 406. When the sleeve is rotated in the opposite direction, itcan cause the distal portion 408 to slide in the opposite direction awayfrom proximal portion 406. Those skilled in the art may appreciate thatin other embodiments, the internally-threaded sleeve can be rotatablyattached to the distal portion 408 of rod 404 and configured to matewith external threading on the proximal portion 408 of the rod.

In some embodiments, the internally-threaded sleeve can be a gearmember. The gear member can include a plurality of teeth extendingaround a periphery of the gear and configured to engage an actuator,such as a tool having a bevel gear. In use, when the tool having a bevelgear engages the teeth and rotates about the axis of the bevel gear, itcan cause the gear member to rotate in a perpendicular direction. As thegear member rotates, its internal threading can engage the externalthreading on the distal portion 408 of the rod 404, causing the distalportion 408 to translate axially.

In other embodiments, the compression member can be disposed within theproximal and/or distal portions 406, 408. In these embodiments, thecompression member can include, for example, a central gear or cam. Inyet other embodiments, the compression member can be disposed betweenthe proximal and/or distal portions 406, 408. In these embodiments, thecompression member can include, for example, a scissor jack or a taperedscrew.

The compression mechanism can optionally include one or more additionalfeatures. For example, some embodiments can include a locking member.The locking member can selectively inhibit rotation of the compressionmember, thereby locking the rod 404 at a particular length. Otherembodiments can include a stabilization assembly. For example, theproximal portion 406 can include a pin configured to ride in alongitudinal slot disposed on the externally-threaded section of thedistal portion 408. In these embodiments, the pin and slot can preventrotational movement of the proximal and distal portions 406, 408. Theends of the slot can also define the maximum allowable distance oftranslational motion for the distal portion 408.

In some embodiments, the compression mechanism 434 can include acompression member configured for linear movement. Linear movement ofthe compression member (e.g., along a transverse axis 442 of the rod404) can result in linear movement of the proximal and/or distalportions 406, 408 in a perpendicular direction (e.g., along thelongitudinal axis 416). For example, in one embodiment, the compressionmechanism 434 can include a body portion and a translation member (shownin FIG. 8). The body portion can be configured to be received betweenthe proximal and distal portions 406, 408 of the rod 404. As shown inFIG. 8, the translation member 480, which may act as the compressionmember, can be configured to be received within the body portion and caninclude a first angled surface 484 and a second angled surface 486.

In some embodiments, the first and second angled surfaces 484, 486 ofthe translation member can be configured to engage the proximal anddistal portions 406, 408 of the rod 404. In some embodiments, theproximal and distal portions 406, 408 can include angled slots, grooves,and/or ramps that correspond to the angled surfaces on the translationmember, and that can be configured to receive a portion of thetranslation member therein. In other embodiments, the proximal anddistal portions 406, 408 can be connected to separate inserts havingangled slots, grooves, and/or ramps that can engage the translationmember. Movement of the translation member along transverse axis 442 cancause the first angled surface to push against the proximal portion 406and the second angled surface to push against the distal portion 408,resulting in compression of the rod 404 (e.g., proximal and distalportions 406, 408 moving towards from each other). In some embodiments,movement of the translation member in the opposite direction alongtransverse axis 442 can result in expansion of the rod 404 (e.g.,proximal and distal portions 406, 408 moving away from each other). FIG.8 illustrates a compression mechanism 434 (e.g., including thetranslation member 480) in a fully contracted or compressed state,rather than in an expanded state.

In other embodiments, the body portion can include a proximal end and adistal end, each of which can include one or more angled slots, grooves,and/or ramps. The angled slots, grooves, and/or ramps can be configuredto receive a protuberance extending from each of the proximal and distalportions 406, 408. In use, translation of the translation member alongtransverse axis 442 can engage the proximal and distal portions 406,408, causing the protuberances to slide along the angled slots, grooves,and/or ramps of the body portion, resulting in compression of the rod404 along longitudinal axis 416. Translation of the translation memberin the opposite direction along transverse axis 442 can cause theprotuberances to also slide in an opposite direction along the angledslots, grooves, and/or ramps of the body portion, resulting in expansionof the rod 404 along longitudinal axis 416.

As illustrated in FIG. 6, the actuator assembly can include an actuator436 located on the proximal portion 406 of the rod 408. For example, theactuator 436 can be located in a proximal cap. The actuator assembly canbe configured to actuate the compression mechanism 434. For example, theactuator assembly can include, for example, a bevel gear, driver,wrench, ratchet, or other torque applicator that is operativelyconnected to the actuator 436 using mechanics known in the art. In someembodiments, the actuator 436 can be selected from a button, switch,knob, threaded nut, and lever.

As illustrated in FIG. 6, compression mechanism 434 can be disposedbetween the proximal and distal portions 406, 408 of the rod 404.However, in other embodiments, the compression mechanism can be locatedat the proximal end of the rod 404. For example, both the compressionmechanism and the actuator can be located in a proximal cap 438,illustrated in FIG. 7. In some of these embodiments, a portion of therod 404 can be received within the proximal cap 438 as part of thecompression process. The proximal cap 438 can be situated at theproximal-most end of the rod 404. In some embodiments, the proximal cap438 can further include a compression slot 440, which can be configuredto facilitate translational movement of the rod 404 towards the proximalcap 438. In some embodiments, the compression cap can serve as anactuator to actuate the compression mechanism 434 located at thejunction between the proximal portion 406 and distal portion 408 of therod 404.

While the previous embodiments disclosed expansion and contraction of anintramedullary nail in an axial direction, in some embodiments, anintramedullary nail can be expanded in a radial direction. Any of themechanisms discussed above, such as the use of ramped surfaces (shown inFIG. 8), can be used to expand an intramedullary nail in a radialdirection. Advantageously, by expanding the intramedullary nail in aradial direction, this allows the intramedullary nail to increase agreater volume in the intramedullary canal, thereby reducing thelikelihood of undesired rotation or movement of the nail within thecanal. In some embodiments, radial expansion of the intramedullary nailin a radial direction results in a shortening of the length of theintramedullary nail, while in other embodiments, the length of theintramedullary nail can be kept substantially or completely constantduring radial expansion.

In some embodiments, the intramedullary nail is capable of either axialor radial expansion/compression. In other embodiments, theintramedullary nail is capable of both axial and radialexpansion/compression. The axial expansion/compression can beindependent from the radial expansion/compression. In some embodiments,a first mechanism can control the axial expansion/compression, while asecond mechanism can control the radial expansion/compression. In someembodiments, the mechanism for axial expansion/compression can be thesame as the mechanism for radial expansion/compression, while in otherembodiments, the mechanisms can be different. For example, axial changescan be made via a ramping mechanism, while radial changes can be madevia a gear expansion mechanism.

Some embodiments herein are directed to a method of installing theintramedullary nail 402. Optionally, the medullary canal may be preparedprior to installation of the intramedullary nail, as described hereinwith respect to other embodiments. Methods of installing intramedullarynail 402 can include providing the intramedullary nail 402 and insertingit, in the expanded configuration, into a medullary canal of a fracturedbone. The fractured bone can include a first bone fragment and a secondbone fragment separated by a first distance. The distal portion 408 ofthe rod 404 can then be secured to the first bone fragment, e.g., viakeels and/or locking screws as described herein. Subsequently, thecompression mechanism 434 can be actuated, thereby transitioning the rodfrom the expanded configuration to the compressed configuration. Thecompression mechanism can be activated by actuating the actuator 436.For example, the rod 404 can be compressed by pushing a button, slidinga switch, turning a knob, threading a nut, and/or pulling a leverlocated on or in the proximal cap 438. The distal portion 408 and thefirst bone fragment can thereby be moved axially (e.g., proximally) to asecond position. In the second, compressed position, the first andsecond bone fragments can be compressed such that they are separated bya second distance that is less than the first distance. In someembodiments, the intramedullary nail 402 can then be secured to thesecond bone fragment, e.g., via keels and/or locking screws. Asdiscussed herein, the compression of the bone fragments canadvantageously promote healing of the fracture and/or reduce recoverytime.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims. Althoughindividual embodiments are discussed herein, the invention covers allcombinations of all those embodiments.

What is claimed is:
 1. An intramedullary nail comprising: a rod having alongitudinal axis, the rod comprising a proximal portion and a distalportion; and at least one elongate keel disposed longitudinally on anouter surface of the rod and radially extending outward relative to thelongitudinal axis of the rod, wherein the intramedullary nail isconfigured to expand axially and radially, the axial expansion beingindependent from the radial expansion, wherein the at least one elongatekeel is not elastically deformable, and wherein the axial expansion ofthe intramedullary nail is a non-magnetic mechanical expansion.
 2. Theintramedullary nail of claim 1, wherein the proximal portion and thedistal portion each comprise a plurality of elongate keels.
 3. Theintramedullary nail of claim 1, wherein the elongate keel has a heightthat increases proximally.
 4. The intramedullary nail of claim 1,wherein the elongate keel extends orthogonally from a surface of therod.
 5. The intramedullary nail of claim 1, wherein the elongate keelhas a length that is equal to at least 10% of a length of the rod. 6.The intramedullary nail of claim 1, wherein the elongate keel comprisesa base, and wherein the elongate keel is attached to an outer surface ofthe rod at the base.
 7. An intramedullary nail comprising: a rodcomprising a proximal portion, a distal portion, and an outer surface;and a deployable keel oriented longitudinally along the rod, thedeployable keel having a fixed height and width; wherein the deployablekeel is configured to transition from a retracted position to a deployedposition where at least a portion of the deployable keel extendsradially outward from the rod, and wherein the deployable keel is notelastically deformable, and wherein the deployable keel non-rotatablytransitions from the retracted position to the deployed position.
 8. Theintramedullary nail of claim 7, wherein the deployable keel comprises atip, and wherein the tip is closer to the outer surface when in theretracted position as compared to the deployed position.
 9. Theintramedullary nail of claim 7, further comprising a deploymentmechanism disposed at a proximal end of the rod and configured toactuate the transition of the deployable keel from the retractedposition to the deployed position.
 10. The intramedullary nail of claim9, wherein the deployment mechanism comprises an actuator located in theproximal cap, and wherein the actuator is selected from the groupconsisting of a button, switch, knob, threaded nut, and lever.
 11. Theintramedullary nail of claim 9, wherein the rod further comprises: alumen extending therethrough from a proximal end to a distal end; and atleast one opening disposed along the rod and configured to receive atleast a portion of the deployable keel.
 12. The intramedullary nail ofclaim 11, wherein: at least a portion of the deployable keel is withinthe lumen when in the retracted position and outside of the lumen whenin the deployed position; and the deployable keel is configured to passthrough the opening when transitioning from the retracted position tothe deployed position.
 13. An intramedullary nail comprising: a rodcomprising a proximal portion and a distal portion and configured totransition from an expanded configuration to a compressed configuration;a compression mechanism configured to move the proximal and distalportions axially with respect to one another from the expandedconfiguration to the compressed configuration; and an actuator assemblyconfigured to actuate the compression mechanism and comprising anactuator located on the proximal portion of the rod, wherein theintramedullary nail is expandable in a radial direction, and thetransition from the expanded configuration to the compressedconfiguration is independent from the expansion in the radial direction,and wherein the expansion of the intramedullary nail in a radialdirection results in the increase in the volume of the intramedullarynail.
 14. The intramedullary nail of claim 13, wherein the compressionmechanism comprises a compression member configured for rotationalmovement.
 15. The intramedullary nail of claim 13, wherein thecompression mechanism comprises an internally-threaded sleeve rotatablyattached around the proximal portion of the rod and configured to matewith external threading on the distal portion of the rod.
 16. Theintramedullary nail of claim 15, wherein the internally-threaded sleeveis a gear member comprising a plurality of teeth extending around aperiphery of the gear member.
 17. The intramedullary nail of claim 13,wherein the compression mechanism comprises a compression memberconfigured for linear movement.
 18. The intramedullary nail of claim 13,wherein the compression mechanism comprises: a body portion configuredto be received between the proximal portion and the distal portion ofthe rod; and a translation member configured to be received within thebody portion and comprising a first angled surface configured to engagethe proximal portion of the rod and a second angled surface configuredto engage the distal portion of the rod.
 19. The intramedullary nail ofclaim 13, wherein the compression mechanism is disposed between theproximal portion and the distal portion of the rod.
 20. Theintramedullary nail of claim 13, wherein the compression mechanism andthe actuator are each located in a proximal cap.